1 /* $Id: bsd-poll.c,v 1.4 2008/08/29 21:32:38 dtucker Exp $ */
4 * Copyright (c) 2004, 2005, 2007 Darren Tucker (dtucker at zip com au).
6 * Permission to use, copy, modify, and distribute this software for any
7 * purpose with or without fee is hereby granted, provided that the above
8 * copyright notice and this permission notice appear in all copies.
10 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
11 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
12 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
13 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
14 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
15 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
16 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
20 #if !defined(HAVE_POLL)
22 #ifdef HAVE_SYS_SELECT_H
23 # include <sys/select.h>
31 * A minimal implementation of poll(2), built on top of select(2).
33 * Only supports POLLIN and POLLOUT flags in pfd.events, and POLLIN, POLLOUT
34 * and POLLERR flags in revents.
36 * Supports pfd.fd = -1 meaning "unused" although it's not standard.
40 poll(struct pollfd *fds, nfds_t nfds, int timeout)
43 int saved_errno, ret, fd, maxfd = 0;
44 fd_set *readfds = NULL, *writefds = NULL, *exceptfds = NULL;
46 struct timeval tv, *tvp = NULL;
48 for (i = 0; i < nfds; i++) {
50 if (fd >= FD_SETSIZE) {
54 maxfd = MAX(maxfd, fd);
57 nmemb = howmany(maxfd + 1 , NFDBITS);
58 if ((readfds = calloc(nmemb, sizeof(fd_mask))) == NULL ||
59 (writefds = calloc(nmemb, sizeof(fd_mask))) == NULL ||
60 (exceptfds = calloc(nmemb, sizeof(fd_mask))) == NULL) {
66 /* populate event bit vectors for the events we're interested in */
67 for (i = 0; i < nfds; i++) {
71 if (fds[i].events & POLLIN) {
73 FD_SET(fd, exceptfds);
75 if (fds[i].events & POLLOUT) {
77 FD_SET(fd, exceptfds);
81 /* poll timeout is msec, select is timeval (sec + usec) */
83 tv.tv_sec = timeout / 1000;
84 tv.tv_usec = (timeout % 1000) * 1000;
88 ret = select(maxfd + 1, readfds, writefds, exceptfds, tvp);
91 /* scan through select results and set poll() flags */
92 for (i = 0; i < nfds; i++) {
97 if (FD_ISSET(fd, readfds)) {
98 fds[i].revents |= POLLIN;
100 if (FD_ISSET(fd, writefds)) {
101 fds[i].revents |= POLLOUT;
103 if (FD_ISSET(fd, exceptfds)) {
104 fds[i].revents |= POLLERR;
111 if (writefds != NULL)
113 if (exceptfds != NULL)